Stockholders' Equity - Additional Information (Detail) - USD ($)			1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 27, 2016	Apr. 15, 2016	Feb. 29, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Apr. 30, 2016	Apr. 05, 2016	Nov. 30, 2014
Sale Of Stock [Line Items]
Common stock, shares issued				7,235,841		7,201,774
Proceeds from issuance of common stock, net				$ 98,744	$ 531,620
Legal, Accounting and Filing Fees				138,000
Payroll withholdings from employees				$ 99,000	$ 111,000
Common stock for Employee Stock Purchase Plan				34,067	23,288
Number of stock options exchanged, outstanding			703,500
Unrecognized compensation costs				$ 2,700,000
Weighted average period				1 year 3 months 18 days
One-Time Option Exchange Program [Member]
Sale Of Stock [Line Items]
Number of stock options exchanged, outstanding			527,624
Number of stock options exchange percentage			75.00%
Options available for future grant			175,876
Options granted, vesting period			3 years
Replacement stock options exercise price			$ 3.04
Incremental compensation expense during period under option exchange			$ 4,700
Unrecognized compensation costs			$ 141,000
Weighted average period			3 years
Subsequent Event | Amended and Restated Equity Incentive Plan 2013 [Member]
Sale Of Stock [Line Items]
Increase in number of shares of common stock reserved under the plan	500,000
Aggregate number of shares of common stock reserved under the plan	4,786,425
Award plan expiration year	2026
MLV Sales Agreement [Member]
Sale Of Stock [Line Items]
Common stock, value of shares issuable									$ 6,600,000
Common stock, shares issued				0		1,048,507
Common stock , weighted average price per share						$ 4.78
Proceeds from issuance of common stock, net						$ 4,900,000
FBR Sales Agreement [Member] | Subsequent Event
Sale Of Stock [Line Items]
Common stock, shares issuable		649,074
Entity public float, common stock shares							4,200,000
Entity public float							$ 23,100,000
Common stock, closing price								$ 5.50
One third value of entity public float							$ 7,700,000
Aggregate market value of entity common stock held by non affiliates		$ 75,000,000